I have 2 older PTP800 units on the shelf and cannot figure out how to use recovery button to reset configuration on these units.
Here is the "Using recovery mode" section from the PTP 800 Series 06-02 User Guide.
I hope this helps!
I have an 810 model with the same issue. The procedure in the manual says wait for the status LED on the control board to flash between green and red alternately, however, the light changes from green (from initial power on) to orange at 2 min. 12 sec. I've tried hitting the call button at around this time on multiple attempts, but I cannot get the device to restore the default values. I need to do this because the IP address is unknown.
For the PTP 810 MMU, you probably just need to wait a little longer for the red and green flashing LED. I just tried this and the status LED starts flashing Red/Green at around 3 minutes and 15 seconds.
Just had to wait over 4 min to see the LED flash.